Breast pump



FIG. 1 is a top, front and side perspective view of a breast pump showing my design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is an opposite side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

Portions of the breast pump shown in broken lines form no part of the claimed design. 

CLAIM The ornamental design for a breast pump, as shown and described. 